Induction of CC and CXC chemokines in human antigen-presenting dendritic cells by the pneumococcal proteins pneumolysin and CbpA, and the role played by toll-like receptor 4, NF-kappaB, and mitogen-activated protein kinases.
BACKGROUND
Choline-binding protein A (CbpA) and pneumolysin (Ply) can induce the expression and release of chemokines by human cells, which might modulate specific immune responses. In dendritic cells (DCs), such effects could be important for the size and character of the immunity induced if administered as vaccines. We studied the induction of CCL and CXCL chemokines by CbpA and Ply in DCs and related signaling pathways.


METHODS
Proteins derived from bacterial cultures and cloning were used as stimulants. DCs were generated from CD14+ human monocytes by negative selection, followed by coculture with recombinant human granulocyte-macrophage colony-stimulating factor and recombinant interleukin-4. The role played by Toll-like receptors (TLRs) was assessed using anti-TLR antibodies. Likewise, specific inhibitors (given in parentheses) of signaling molecules were used: NF-kappaB (SN50), extracellular signal-regulated kinase (PD98059), p38 (SB203580), and Jun N-terminal kinase (SP600125).


RESULTS
Both CbpA and Ply significantly up-regulated DC mRNA of several CCL (2, 4, 5, and 8) and CXCL (8 and 10) chemokines studied as well as the expression of 3 proteins studied: CCL2, CCL5, and CXCL8. Ply stimulation was blocked by anti-TLR4. Inhibition of NF-kappaB and several mitogen-activated protein kinase signaling pathways also reduced chemokine release.


CONCLUSIONS
Chemokine induction in DCs by CbpA and Ply may be important for their potential use in future pneumococcal vaccines.
Bernatoniene
Jolanta
J
Institute of Child Life and Health, University of Bristol, Bristol, United Kingdom.
Zhang
Qibo
Q
Dogan
Semih
S
Mitchell
Tim J
TJ
Paton
James C
JC
Finn
Adam
A
D001426:Bacterial Proteins / Q000494:pharmacology*; D002478:Cells, Cultured; D019742:Chemokines, CC / Q000235:genetics / Q000378:metabolism*; D019743:Chemokines, CXC / Q000235:genetics / Q000378:metabolism*; D017077:Culture Media, Conditioned; D003713:Dendritic Cells / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism*; D015398:Signal Transduction; D013301:Streptolysins / Q000494:pharmacology*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
D001426:Bacterial Proteins; C490083:CbpA protein, bacteria; D019742:Chemokines, CC; D019743:Chemokines, CXC; D017077:Culture Media, Conditioned; D016328:NF-kappa B; D013301:Streptolysins; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C032290:plY protein, Streptococcus pneumoniae; D020929:Mitogen-Activated Protein Kinase Kinases